I'd like to see the Lanun having UBs like those of both Portugal and the Dutch in BtS (for extra gold and production from water tiles), and the ability to blockade for all of their ships (maybe even their workboats). Personally, I think their Harbor should grant the HN promotion to all ships they build, but only if declare nationality is changed a little. Personally I think it should work more like a vampires feed ability than a spell, i.e., it shouldn't call canCast(caster) or doCast(caster) so that it could be used at anytime, even just before or after attacking. Also, I think HN units should be able to capture other units,at least if you are at war with their owner. Lastly, I would consider giving the Boarding Party promotion to the Black Wind and possibly their late game ships, giving the Lanun total control of the seas.
As I have said before, I think that the Pirates cove should become a unique Fort which can still grant the Pirates cove promotion to ships on the tile, but would more importantly be able to blockade a large amount of the surrounding seas on its own, or greatly increase the blockade range of ships on the tile.
Coral seems more like a terrain feature than a resource, sort of like forests for the coasts. It might be interesting as a feature that was good for boosting a tile's food, gold, or production, but had a high chance of making ships crash an sink (a possible new special event, which could be weighed so that it doesn't happen to the Lanun as often or at all). I'm not a huge fan of adding more resources, just because I'm not sure if the team has solved the problem imiting their total number to 50 yet, and I don't want to lose another of the current ones. Could the current dyes resource be made harvestable with either plantations or fishingboats, but only the Lanun could build fishing boats over them?